title: A straight left heart border: a new radiological sign of a hemopericardium.
abstract: BACKGROUND
  Detection of a cardiac injury in a stable patient after a penetrating chest injury can be difficult. Ultrasound of the pericardial sac may be associated with a false negative result in the presence of a hemothorax. A filling in of the left heart border inferior to the pulmonary artery, called the straight left heart border (SLHB), is a radiological sign on chest X-ray that we have found to be associated with the finding of a hemopericardium at surgery. The aim of the present study was to determine if this was a reliable and reproducible sign.
  
  
  METHODS
  This was a prospective study of patients with a penetrating chest injury admitted between 1 October 2001 and 28 February 2009, who had no indication for immediate surgery, and were taken to the operating room for creation of a subxiphoid pericardial window (SPW). The chest X-ray was reviewed by a single trauma surgeon prior to surgery.
  
  
  RESULTS
  A total of 162 patients with a possible occult cardiac injury underwent creation of a SPW. Fifty-five of the 162 patients (34 %) were noted to have a SLHB on chest X-ray and a hemopericardium confirmed at SPW. The sensitivity of the SLHB sign was 40 %; specificity, 84 %; and positive predictive value, 89 %. (p = 0.005, Odds ratio 3.48, lower 1.41, upper 8.62).
  
  
  CONCLUSIONS
  The straight left heart border is a newly described radiological sign that was highly significant in predicting the presence of a hemopericardium and should alert the clinician to a possible occult cardiac injury.
authors.affiliation: Trauma Centre, Department of Surgery, Groote Schuur Hospital, University of Cape Town, Anzio Road, Cape Town, 7925, South Africa, andrew.nicol@uct.ac.za.
authors.forename: Andrew John
authors.initials: AJ
authors.lastname: Nicol
authors.forename: Pradeep Harkison
authors.initials: PH
authors.lastname: Navsaria
authors.forename: Steve
authors.initials: S
authors.lastname: Beningfield
authors.forename: Delawir
authors.initials: D
authors.lastname: Kahn
mesh_terms: D000293:Adolescent; D000328:Adult; D006335:Heart Injuries / Q000150:complications / Q000000981:diagnostic imaging*; D006801:Humans; D008875:Middle Aged; D010490:Pericardial Effusion / Q000000981:diagnostic imaging* / Q000209:etiology; D011446:Prospective Studies; D011859:Radiography; D015203:Reproducibility of Results; D055815:Young Adult